Methods and systems for improving the operation of transmissions for motor vehicles

ABSTRACT

Methods and systems for improving the operation of a transmission for an automotive vehicle are provided for modifiying the original hydraulic circuits to increase the capacity or holding ability of the low and reverse clutches when the transmission is shifted into manual low gear to slow down a moving vehicle, to provide a quick and smooth apply of the low and reverse clutches when the driver selects manual low when the vehicle is moving at a relatively high road speed, and to permit the connection of two low hydraulic circuits to feed torque converter and cooler/lubrication circuits by application of relatively low fluid pressure to assure that the necessary pressure required to connect the circuits will be properly applied.

BACKGROUND OF THE INVENTION

The methods and systems of the present invention are directed to themodification and improvement of transmissions for automotive vehicles ofthe type installed by the original equipment manufacturer, commonlyreferred to as the “factory installed” transmission.

The invention is particularly directed to improvement and modificationof the automotive transmissions commonly known as the 4R100 installed invehicles manufactured by the Ford Motor Company of Dearborn, Mich., andthe E40D also installed in vehicles manufactured by the Ford MotorCompany of Dearborn, Mich.

The present inventor owns the following United States patents, thedisclosure of each of which is expressly incorporated by reference intothe present application: U.S. Pat. No. 4,449,426, issued May 26, 1984;U.S. Pat. No. 4,711,140, issued Dec. 8, 1987; U.S. Pat. No. 4,790,938,issued Dec. 13, 1988; U.S. Pat. No. 5,253,549, issued Oct. 19, 1993;U.S. Pat. No. 5,540,628, issued Jul. 30, 1996; U.S. Pat. No. 5,624,342,issued Apr. 29, 1997; U.S. Pat. No. 5,730,685, issued Mar. 24, 1998;U.S. Pat. No. 5,743,823, issued Apr. 28, 1998; U.S. Pat. No. 5,768,953,issued Jun. 23, 1998; U.S. Pat. No. 5,820,507, issued Oct. 7, 1998; U.S.Pat. No. 5,967,928, issued Oct. 19, 1999; U.S. Pat. No. 6,099,429,issued Aug. 8, 2000; U.S. Pat. No. 6,117,047, issued Sep. 12, 2000; U.S.Pat. No. 6,287,231, issued Sep. 11, 2001; U.S. Pat. No. 6,390,944,issued May 21, 2002; and U.S. Pat. No. 6,565,472, issued May 20, 2003.

Applicant also owns the following pending U.S. patent applications: Ser.No. 10/081,605, filed Feb. 21, 2002 (now U.S. Pat. No. 6,871,397, issuedMar. 29, 2005); Ser. No. 10/105,674, filed Mar. 25, 2002 (now U.S. Pat.No. 6,699,157, issued Mar. 2, 2004) ; Ser. No. 10/348,846, filed Jan.22, 2003 (now U.S. Pat. No. 6,729,989, issued May 4, 2004); Ser. No.10/360,576, filed Feb. 7, 2003 (now U.S. Pat. No. 6,814,680, issued Nov.9, 2004); and Ser. No. 10/678,924, filed Oct. 3, 2003.

The basic principles of the “factory installed” 4R100 automotivetransmission, including the specific modes of operation thereof and thehyrdraulic circuits and interrelationship of hyrdraulic circuits, arewell known to those in the automotive transmission art. Attention isrespectfully invited to the operations manual and text entitled 4R100Transmissions—Theory And Operation (2000), published by Ford MotorCompany of Dearborn, Mich., said publication describing in detail theoperation of the “factory installed” 4R100 automotive transmission,including a description of the structure, the hydraulic circuits, andthe interrelationship between the structure and the hydraulic circuitryand fluid flow during normal operation of this “factory installed”transmission in automotive vehicles. The disclosure of theaforementioned publication in its entirety is expressly incorporated byreference into the disclosure of the present patent application asdisclosing and illustrating background material known to those ofordinary skill in the automotive transmission art.

The basic principles of operation of the “factory installed” E40Dtransmission for automotive transmissions, including the specific modesof operation thereof and the hydraulic circuits and interrelationship ofhydraulic circuits, are well known to those skilled in the automotivetransmission art. Attention is respectfully invited to the operationsmanual and text entitled E40D Automotive Transmission Reference Manual(1992), published by Ford Motor Company of Dearborn, Mich., saidpublication describing in detail the operation of the “factoryinstalled” E40D transmission, including a discussion of the structure,the hydraulic circuits, and the interrelationship between the structureand the hydraulic circuitry and fluid flow during normal operation ofthis “factory installed” transmission in automotive vehicles. Thedisclosure of the aforementioned publication in its entirety isexpressly incorporated by reference into the disclosure of the presentpatent application as disclosing the illustrating background materialknown to those of ordinary skill in the automotive transmission art.

It is a primary objective of the present invention to increase thecapacity or holding ability of the low and reverse clutches of the“factory installed” 4R100 and E40D transmissions when the transmissionis shifted into manual low gear to slow the vehicle, as for example,when the vehicle is descending downhill. Heavy loaded vehicles may causethe low and reverse clutches of the “factory installed” transmissions toburn and fail rapidly when the transmissions are used under theseconditions.

It is a further object of the present invention to provide a quick, butsmooth, apply of the low and reverse clutches in the “factory installed”4R100 and E40D transmissions when the driver selects manual low gearwhen the vehicle is travelling at a relatively high road speed. A roughapply may result in tire skidding, while a slow apply may result in afree-wheeling or neutral condition.

It is yet a further object of the present invention to modify the“factory installed” 4R100 and E40D transmissions to adjust the pressurerequired to move the pressure regulator valve into a position forapplying fluid to the torque converter and cooler/lubrication circuitsat a pressure less than that required by the “factory installed”transmissions. In the “factory installed” transmissions, a pressure ofapproximately 75 psi or higher must be applied to a pressure regulatorvalve by the output of a pressure pump to result in the flow of applypressure to the torque converter and cooler/lubrication circuits. Whenthe transmission is worn and/or leaks develop, the pump outlet cannotprovide the necessary threshold pressure to feed the torque converterand cooler/lubrication circuits resulting in converter, bushing and gearfailure as a result of lack of lubrication. By modifying the hydrauliccircuitry of the “factory installed” transmission to require asignificantly lower threshold pressure to feed the torque converter andcooler/lubrication circuits, the required apply pressure is providednotwithstanding worn components or leaks in the transmission.

Other objects and advantages of the improvements to the “factoryinstalled” 4R100 and E40D automotive transmissions in accordance withthe present invention will become apparent from the following discussionthereof in conjunction with the drawings.

SUMMARY OF THE INVENTION

The present invention provides methods and systems for modifying thehydraulic circuitry of a “factory installed” automotive transmission,and in particular the automotive transmissions designated as 4R100 andE40D by the Ford Motor Company. In accordance with a first aspect of theinvention, the hydraulic circuitry of the “factory installed”transmissions is modified such that line pressure is initially appliedto a 4-3-2 manual timing valve at full flow through a first hydrauliccircuit for applying the fluid pressure to the low/reverse modulatorvalve until a predetermined pressure is attained, and thereafter fluidpressure is applied to the 4-3-2 manual timing valve through a secondhydraulic circuit at a reduced flow rate until the fluid pressureapplied to the low/reverse modulator valve attains a desired value. Byswitching the hydraulic circuit feeding the 4-3-2 manual timing valvefrom full flow below a predetermined pressure value to a reduced flowwhen the predetermined pressure value is attained, pressure is appliedto the low/reverse modulator valve and the low and reverse clutchesquickly but smoothly when the driver of the vehicle shifts thetransmission into a manual low gear position when the vehicle is beingdriven at a relatively high road speed. In this manner, a rough apply,which could result in tire skidding, and a slow apply, which can resultin a free-wheeling or neutral condition of the vehicle, is avoided.Additionally, the capacity or holding ability of the low and reverseclutches is increased to assist the vehicle when the transmission isplaced in manual low to slow the vehicle, as for example, when thevehicle is descending downhill. The boost valve acting on thelow/reverse modulator valve of the “factory installed” transmission isprovided with a larger diameter, thereby enabling the new boost valve toapply a greater pressure to the low/reverse modulator valve and thus tothe low and reverse clutches, than is possible with the “factoryinstalled” transmission.

In a further aspect of the invention, the “factory installed”transmissions are modified so that a lower apply fluid pressure iscapable of moving the pressure regulator valve to apply fluid to thetorque converter and the cooler/lubrication circuits. In this manner,older transmissions with worn components or leaks, which otherwise wouldnot be capable of applying sufficient pressure to the pressure regulatorvalve to feed the torque converter and cooler/lubrication circuits, aremodified so that significantly less fluid pressure is necessary to feedthe torque converter and cooler/lubrication circuits.

This modification is accomplished by providing a new spring seat on thepressure regulator valve mounted to an existing casting for permittingthe pressure regulator valve to move a predetermined distance necessaryto feed the torque converter cooler/lubrication circuits before thepressure regulator valve engages the seat, such movement of the pressureregulator valve being accomplished by the application of less applyfluid pressure than required by the “factory installed” transmission. Inthis manner, converter, bushing and gear failure as a result of lack oflubrication resulting from the failure of the “factory installed”transmission to apply the requisite fluid pressure to feed the converterand cooler/lubrication circuits, is avoided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A–1D illustrate the hydraulic circuitry of a 4R100 automotivetransmission, as modified in accordance with the present invention;

FIG. 2 illustrates a portion of the hydraulic circuitry of FIG. 1showing the modifications in greater detail; and

FIG. 3 illustrates a portion of the hydraulic circuitry of a “factoryinstalled” 4R100 automotive transmission showing further modificationsmade to the main regulator valve in accordance with the presentinvention.

DESCRIPTION OF THE BEST MODES FOR CARRYING OUT THE INVENTION

FIG. 1 of the drawing illustrates the hydraulic system of a “factoryinstalled” 4R100 automotive transmission, as modified in accordance withone aspect of the present invention. FIG. 2 illustrates a portion of thehydraulic circuitry illustrated in FIG. 1, showing the modificationsmade to the hydraulic circuitry in greater detail. Although thefollowing discussion of modifications to the hydraulic circuitry of a“factory installed” transmission refers primarily to the 4R100automotive transmission installed in vehicles produced by the Ford MotorCompany, the discussion is equally applicable to modifications to theE40D automotive transmission also installed in vehicles produced by theFord Motor Company.

The hydraulic circuitry of the automotive transmission illustrated byFIGS. 1 and 2 of the drawing includes a manual valve designated byreference numeral 2. When manual low gear is selected by the driver ofthe vehicle at relatively high road speeds, the manual valve 2 feedsmain line oil pressure to fluid flow passageways designated by referencenumerals 4 and 6. The manual valve 2 is in fluid communication with thepassageways 4 and 6 by a fluid flow channel designated by referencenumeral 8. Fluid flow passageway 6 permits full flow of fluidtherethrough, while fluid flow passageway 4 has a restricted diameter(0.056 inches in the “factory installed” transmission) for restrictingfluid flow through this passageway.

Both fluid flow passageways 4 and 6 are coupled in fluid communicationto a 4-3-2 manual timing valve generally designated by reference numeral10. A fluid flow passageway, designated generally by reference numeral12, couples the manual timing valve 10 in fluid communication with themanual valve 2. A fluid flow passageway, designated by the referencenumeral 14, couples the manual timing valve 10 in fluid communicationwith a low and reverse modulator valve designated generally by referencenumeral 16.

When the manual timing valve 10 is in its most leftward position asviewed in FIGS. 1 and 2 of the drawing, the fluid flow passageways 12and 14 are coupled in fluid communication to each other through themanual timing valve 10, and fluid is fed to the low and reversemodulator valve through the channel 14. As noted above, full main linepressure is applied to the manual timing valve 10 through fluid flowpassageway 6, while restricted flow of main line pressure is applied tothe manual timing valve 10 through fluid flow passageway 4. In the“factory installed” transmission, both the full main line pressurethrough passageway 6, and the restricted main line pressure throughpassageway 4, are simultaneously applied to the manual timing valve 10.As such, full main line pressure is applied to the low and reversemodulator valve 16 through the channel 14 coupling the manual timingvalve 10 and the low and reverse modulator valve 16, without regard tothe position of the manual timing valve 10. The diameter of a boostvalve, designated by reference numeral 18 and positioned at the rightend of the low and reverse modulator valve 16 as viewed in FIGS. 1 and2, regulates the low and reverse clutch fluid pressure applied by thelow and reverse modulator valve to the low and reverse clutches. In the“factory installed” transmission, the boost valve diameter is selectedto regulate the low and reverse clutch pressure to 30 psi. Therefore, inthe “factory installed” transmission, the low and reverse clutches arefed with a fluid pressure of 30 psi at all times, without regard to theposition of the manual timing valve 10, when the driver of the vehiclemoves the manual valve to select a manual low gear position. The resultis that the low and reverse clutches of the “factory installed”transmission are abruptly applied, and the maximum pressure applied isrelatively low and adversely affects the holding ability of the low andreverse clutches. This, in turn, adversely affects the operation of thevehicle when, for example, the transmission is shifted into a manual lowgear position to slow the vehicle when the vehicle is descendingdownhill, which may cause the low and reverse clutches to rapidly fail.Additionally, the abrupt application of the low and reverse clutcheswhen the transmission is shifted into a manual low gear when the vehicleis travelling at relatively high road speeds can result in skidding,while the application of the low and reverse clutches too slowly mayresult in a free-wheeling or neutral condition of the vehicle.

In accordance with one aspect of the present invention, the “factoryinstalled” hydraulic circuitry of the automotive transmission ismodified to quickly but smoothly apply the low and reverse clutches whenthe driver of the vehicle selects a manual low gear position when thevehicle is travelling at a relatively high road speed. The modificationsto the “factory installed” transmission also increase the capacity orholding ability of the low and reverse clutches by increasing themaximum apply pressure generated by the low and reverse modulator valve.These results are accomplished by modifying the hydraulic circuitry ofthe “factory installed” transmission in the manner discussed as follows.

In accordance with the present invention, a new manual timing valve 10,which replaces the manual timing valve of the “factory installed”transmission, includes an additional land which blocks flow of fluidthrough passageway 6 once a pressure of 48 psi is applied to the manualtiming valve 10 through passageway 4. When fluid flow through passageway6 is blocked, only the reduced flow of fluid through passageway 4 isapplied to the low and reverse modulator valve 16 through fluid flowchannel 14. This produces a gradual (non-abrupt) but firm application offluid to the low and reverse modulator valve 16, which in turn resultsin a smooth application of the low and reverse modulator clutch.

In operation of the modified transmission, fluid flow through passageway4 applies a fluid pressure to the left end of the new manual timingvalve 10, forcing it in a rightward direction, as viewed in FIGS. 1 and2, against a return spring designated by reference numeral 20. Theinitial fluid flow through passageway 4 also moves an accumulatorpiston, designated by reference numeral 22, leftward as viewed in FIGS.1 and 2, against a return spring designated by reference numeral 24.Moreover, a new passageway designated by reference numeral 26 isprovided to apply supplemental fluid pressure to the left side of theaccumulator piston 22, to supplement the force of the return spring 24acting on the left side of the accumulator piston 22 as viewed in FIGS.1 and 2. Fluid flow through the passageway 26 is controlled by asolenoid (not shown).

When the fluid pressure applied to the manual timing valve 10 throughfluid flow passageway 4 reaches 48 psi, the manual timing valve 10 ismoved into a position in which the land added to the manual timing valve10 blocks the outlet of fluid flow passageway 6 to cut-off any furtherpressure applied to the manual timing valve 10 through passageway 6.Thereafter, all fluid pressure applied to the manual timing valve 10 isfrom fluid flowing exclusively through passageway 4, which as notedabove, is reduced in diameter to reduce fluid flow therethrough. Thereduced fluid flow through passageway 4 is applied, through the manualtiming valve 10 and the fluid flow channel 14, to the low and reversemodulator valve 16, until maximum applied pressure has been achieved. Bycutting off the full fluid flow from passageway 6 after a predeterminedfluid pressure applied to the manual timing valve 10 has been achieved,further pressure applied to the manual timing valve exclusively throughthe reduced diameter passageway 4 results in a firm but gradual(non-abrupt) application of fluid pressure to the low and reversemodulator valve 16 through the manual timing valve 10 and the fluid flowchannel 14. This, in turn, results in a firm but gradual application ofthe low and reverse modulator clutches, which avoids a skiddingcondition which might occur if a vehicle is shifted into manual low gearat a relatively high road speed, or a free-wheeling or neutral conditionwhich might occur if the vehicle is shifted into manual low gear tooslowly. The firm, continuous and non-abrupt application of fluidpressure to the low and reverse modulator valve 16 avoids these twoextreme conditions.

The characteristics of the return spring 20 of the manual timing valve10, the return spring 24 of the accumulator piston 22, and the fluidpressure applied to the left end of the accumulator piston through fluidflow passageway 26, are selected to cooperate with each other to assurethat the fluid pressure applied to the low and reverse modulator valvethrough the manual timing valve is firm, continuous and non-abrupt. Itis apparent that the rate at which fluid pressure is applied to the lowand reverse modulator valve 16 through the manual timing valve 10, andthe maximum fluid pressure applied, are adjustable by adjusting thecharacteristic of the return spring 20, and/or the characteristic of thereturn spring 24, and/or the fluid pressure applied to the accumulatorpiston 22 through the passageway 26.

As discussed above, the “factory installed” transmission is designed toapply a maximum pressure of 30 psi to the low and reverse clutch. Inaccordance with a further aspect of the present invention, the “factoryinstalled” transmission is modified so that a maximum fluid pressure of80 psi is applied to the low and reverse clutch. This modification isaccomplished by replacing the “factory installed” boost valve acting onthe right side of the low and reverse modulator valve 16 as viewed inFIGS. 1 and 2, with a larger diameter boost valve designated byreference numeral 28. The boost valve 28 acts on the low and reversemodulator valve 16 through a spring 18 disposed therebetween. Thediameter of the boost valve controls the maximum pressure applied by thelow and reverse modulator valve 16 to the low and reverse clutch. Byreplacing the “factory installed” boost valve with a larger diameterboost valve, the maximum pressure applied to the low and reversemodulator valve 16 through the manual timing valve 10 is increased.Preferably, in accordance with the modifications to the “factoryinstalled” transmission made by the present invention, the maximum fluidpressure applied to the low and reverse modulator valve, and therefore,the maximum fluid pressure applied to the low and reverse clutch, is 80psi. This is a significant increase over the maximum pressure applied tothe low and reverse clutch by the “factory installed” transmission,which is 30 psi. As a result of the increase of maximum apply pressureto the low and reverse clutch, the holding capacity of the low andreverse clutch is increased, thereby enabling the driver of a vehicle toselect manual low gear to slow the vehicle, when, for example, thevehicle is descending downhill, without resulting in failure or burnoutof the low and reverse clutches.

As a result of the modifications to the “factory installed” transmissionas discussed above, the new manual timing valve feeds full main linepressure to the low and reverse modulator valve 16 until a predeterminedfluid pressure (e.g., 48 psi) is applied to the manual timing valve,after which the pressure applied to the manual timing valve isexclusively from a reduced flow passageway, resulting in a smooth,continuous and non-abrupt application of fluid pressure to the low andreverse modulator valve through the manual timing valve. The boostmodulator valve 28 acting on the right end of the low and reversemodulator valve 16 through the spring 18 is increased in diameter toapply a greater maximum pressure to the low and reverse modulator valve(e.g. 80 psi) than is possible with the “factory installed”transmission. The reverse and modulator clutches are therefore appliedfirmly, but gradually, as a result of the gradual increase in fluidpressure applied to the lower and reverse modulator valve, until the newmaximum fluid pressure is attained. In this manner, skidding andfree-wheeling conditions of the vehicle are avoided when the driverselects manual low gear at relatively high road speeds, and the holdingability of the low and reverse clutches is increased as a result of thesignificant increase to the maximum apply pressure thereby preventingburnout and failure of the low and reverse clutches when manual low gearis selected to slow a moving vehicle.

FIG. 3 illustrates a further modification to the “factory installed”4R100 and E40D automotive transmission in accordance with the presentinvention. The “factory installed” transmission is designed so that pumppressure must exceed a value of 75 psi to open a pressure regulatorvalve necessary to feed the torque converter and cooler/lubricationcircuits. When the transmission is relatively new, the hydraulic systemhas no difficulty in achieving the required threshold pressure to feedthe torque end cooler/lubrication circuits. However, when thetransmission is older and parts become warped or worn, and leaksdevelop, it becomes more difficult for the hydraulic circuitry toachieve the required threshold pressure of 75 psi to open the pressureregulator valve. This problem becomes particularly serious at hot andslow engine/pump speeds when the pump cannot supply sufficient fluidpressure to overcome leaks in the system to achieve the necessary 75 psitheshold pressure to open the pressure regulator valve to feed oil tothe torque converter and cooler/lubrication circuits. As a result, theconverter and lubrication pressure falls to zero, resulting in converterfailure, as well as transmission, bushing and gear failure resultingfrom lack of lubrication.

In accordance with a further aspect of the present invention, the“factory installed” 4R100 and E40D automotive transmissions are modifiedto significantly reduce the threshold pressure necessary to open thepressure regulator valve to feed the torque converter andcooler/lubrication circuits. In this manner, the pump output is capableof generating the necessary output pressure to open the pressureregulator valve to feed the torque converter and cooler/lubricationcircuits, notwithstanding worn components or leaks in the hydrauliccircuitry of the transmission.

FIG. 3 illustrates a new spring seat designated by reference numeral 30mounted on a casting designated by reference numeral 32. The pressureregulated valve, designated by reference numeral 34, is movable upwardlyas seen in FIG. 3, to connect a first fluid circuit designated byreference numeral 36, with a second fluid circuit designated byreference numeral 38. The circuits 36 and 38, in the modifiedtransmission, are connected to each other in fluid flow relationship, asa result of upward movement of a distance of about 0.015 inches by thepressure regulator valve, before the top surface of the valve engagesthe seat 30 which precludes any further upward movement of the valve 34.The necessary movement of the pressure regulator valve to couple thecircuits 36 and 38 occurs when the outlet pump pressure applied to thepressure regulator valve is approximately 15 psi. This pressure isreadily achieved by the hydraulic circuitry, notwithstanding any leaksor worn components which otherwise diminish the outlet pump pressureapplied to the pressure regulator valve in the “factory installed”transmission. Once the pressure regulator valve is moved into engagementwith the seat 30 to connect circuits 36 and 38, the pressure availablefrom the pump outlet applied to the pressure regulator valve isregulated by an outer spring designated by reference numeral 40, thelower end of which is supported by the upper surface of the seat 30. Therelationship between the seat 30 and the outer spring 40 assures thatthe first 15 psi of pressure generated by the pump is dedicatedexclusively to connecting the circuits 36 and 38 to feed oil to thetorque converter and the cooler/lubrication circuits. When the vehicleengine is turned off and the pump no longer generates output pressureapplied to the lower end of the torque converter valve 34 to move thevalve in an upward direction, an inner spring designated by referencenumeral 42 acts on the top surface of the torque converter valve 34 tomove it in a downward direction to block circuits 36 and 38. In thismanner, the fluids in circuits 36 and 38 will remain in the circuits andnot drain back into a lower pan, which would result in delay in feedingthe torque converter and cooler/lubrication circuits when the vehicleengine is turned on and the transmission is back in operation.

The modifications to the hydraulic circuitry of the “factory installed”transmission, as discussed with respect to FIG. 3, prevents converterbushing and gear failure of the transmission resulting from lack oflubrication by modifying the hydraulic circuitry of the “factoryinstalled” transmission to feed the torque converter andcooler/lubrication circuits with oil at a significantly lower pressurethan required by the “factory installed” transmission. In this manner,the necessary threshold pressure is generated notwithstanding leaks inthe hydraulic circuitry and worn components which might otherwiseprevent the “factory installed” transmission from attaining thenecessary fluid pressure to feed the torque converter andcooler/lubrication circuits of the hydraulic circuitry of the automotivetransmission.

Other variations and modifications of the embodiments of the inventiondiscussed herein will become apparent to those skilled in the art.Accordingly, the description of the preferred embodiments are intendedto be illustrative only, but not restrictive of the scope of theinvention, that scope being defined by the following claims and allequivalents thereto.

1. A method for modifying the hydraulic circuitry of a “factoryinstalled” automotive transmission of the type including at least firstand second fluid flow passageways disposed in fluid communicationbetween a “factory installed” manual valve and a “factory installed”manual timing valve, said manual timing valve being disposed in fluidcommunication between said at least first and second fluid flowpassageways and a “factory installed” low and reverse modulator valvesuch that fluid pressure from both of said first and second fluid flowpassageways is simultaneously applied to said low and reverse modulatorvalve through said manual timing valve; the steps of said methodcomprising: modifying said “factory installed” manual timing valve suchthat fluid pressure is applied to said modified manual timing valvesimultaneously from both of said first and second fluid flow passagewaysto move said manual timing valve until a predetermined pressure isapplied thereto, and thereafter causing said manual timing valve toblock fluid flow through said first fluid flow passageway so that fluidpressure is applied to said low and reverse modulator valve through saidmanual timing valve only through said second fluid flow passageway. 2.The method as claimed in claim 1 wherein the step of modifying the“factory installed” manual timing valve includes the step of replacingthe “factory installed” manual timing valve with a manual timing valvedefining a land which blocks fluid flow from said first fluid flowpassageway as a result of said movement of said manual timing valve whensaid predetermined pressure is applied thereto.
 3. The method as claimedin claim 1, further comprising the step of reducing the diameter saidsecond fluid flow passageway disposed in fluid communication betweensaid manual valve and said manual timing valve for reducing the rate offluid flow through said second fluid flow passageway.
 4. The method asclaimed in claim 2, further comprising the step of reducing the diameterof said second fluid flow passageway to reduce the rate of fluid flowthrough said second fluid flow passageway.
 5. The method as claimed inclaim 4, further comprising the step of reducing the rate at which fluidpressure is applied to said low and reverse modulator valve through saidmanual timing valve as a result of the reduced rate of fluid flowthrough said second fluid flow passageway.
 6. The method as claimed inclaim 1, wherein said predetermined pressure does not exceed 48 poundsper square inch.
 7. The method as claimed in claim 3, wherein thereduced diameter of said second fluid flow passageway does not exceed0.56 inches.
 8. The method as claimed in claim 4, wherein the reduceddiameter of second fluid flow passageway does not exceed 0.56 inches. 9.The method as claimed in claim 1, wherein said “factory installed”transmission includes an accumulator piston disposed on one side of saidmanual timing valve, the steps of said method comprising moving theaccumulator piston in a first predetermined direction relative to thesaid manual timing valve by fluid pressure applied to said manual timingvalve through said other of said two fluid flow passageways after saidpredetermined pressure has been applied to said manual timing valve. 10.The method as claimed in claim 9, further comprising the step ofapplying a resilient force to said accumulator piston to oppose movementof said accumulator piston in said first predetermined direction. 11.The method as claimed in claim 9, further comprising the step ofproviding a fluid flow passageway in fluid communication with saidaccumulator piston, said fluid flow passageway arranged to apply a fluidpressure to said accumulator piston to oppose movement of saidaccumulator piston in said first predetermined direction.
 12. The methodas claimed in claim 9, further comprising the steps of: applying aresilient force to said accumulator piston to oppose movement of saidaccumulator piston in said first predetermined direction; and providinga fluid flow passageway in fluid communication with said accumulatorpiston, said fluid flow passageway arranged to apply a fluid pressure tosaid accumulator piston to oppose movement of said accumulator piston insaid first predetermined direction.
 13. A method for modifying thehydraulic circuitry of a “factory installed” automotive transmission ofthe type including at least first and second fluid flow passagewaysdisposed in fluid communication between a “factory installed” manualvalve and a “factory installed” manual timing valve, said manual timingvalve being disposed in fluid communication between said at least firstand second fluid flow passageways and a “factory installed” low andreverse modulator valve such that fluid pressure from both of said firstand second fluid flow passageways is simultaneously applied to said lowand reverse modulator valve through said manual timing valve; the stepsof said method comprising: modifying said “factory installed” manualtiming valve such that fluid pressure is applied to said modified manualtiming valve simultaneously from both of said first and second fluidflow passageways to move said manual timing valve until a predeterminedpressure is applied thereto, and thereafter causing said manual timingvalve to block fluid flow through said first fluid flow passageway sothat fluid pressure is applied to said low and reverse modulator valvethrough said manual timing valve only through said second fluid flowpassageway; wherein said “factory installed” automotive transmissionincludes a boost valve operatively associated with said low and reversemodulator valve for regulating low and reverse clutch pressure, saidmethod further comprising the step of increasing the diameter of theboost valve for increasing the pressure applied to the low and reverseclutch.
 14. The method as claimed in claim 13, wherein the step ofincreasing the diameter of said boost valve includes the step ofincreasing said diameter of said boost valve to a size sufficient toapply a pressure of at least 80 pounds per square inch to the low andreverse clutch.
 15. A method for modifying the hydraulic circuitry of a“factory installed” automotive transmission of the type including atleast two fluid flow passageways disposed in fluid communication betweena “factory installed” manual valve and a “factory installed” manualtiming valve, said manual timing valve being disposed in fluidcommunication between said at least two fluid passageways and a “factoryinstalled” low and reverse modulator valve such that fluid pressure fromboth of said two fluid flow passageways is simultaneously applied tosaid low and reverse modulator valve through said manual timing valve,said “factory installed” automotive transmission further including aboost valve operatively associated with said low and reverse modulatorvalve for regulating low and reverse clutch pressure; the steps of saidmethod comprising: modifying said “factory installed” manual timingvalve such that fluid pressure is applied to said modified manual timingvalve simultaneously from both of said two fluid flow passageways tomove said manual timing valve until a predetermined pressure is appliedthereto, and thereafter causing said manual timing valve to block fluidflow through one of said two fluid flow passageways so that fluidpressure is applied to said low and reverse modulator valve through saidmanual timing valve only through the other of said two fluid flowpassageways; reducing the diameter of one of said two fluid flowpassageways disposed in fluid communication between said manual valveand said manual timing valve for reducing the rate of fluid flow throughsaid one fluid flow passageways; and increasing the diameter of theboost valve for increasing the pressure applied to the low and reverseclutch.